Synchronous self-shifting clutch

ABSTRACT

In a synchronous self-shifting toothed clutch having an intermediate member movable relative to one of the clutch parts to effect at least partial interengagement of the clutch teeth, the said clutch part carries a ring of baulking teeth and the intermediate member carries a toothed locking ring which is rotatable about the clutch axis. In the disengaged condition of the clutch the locking teeth and the baulking teeth are interengaged when the clutch teeth attain at least partial interengagement the locking teeth move axially out of engagement with the baulking teeth and the locking ring is rotated by springs to a position in which disengagement of the clutch teeth is prevented due to the baulking teeth being in baulking relationship with the locking teeth. Fluid pressure acts automatically, when the clutch attains a predetermined rotational speed, to return the locking ring to a position in which the locking teeth can interengage with the baulking teeth to permit the clutch to disengage.

i] ite Sttes Clements et al.

atent SYNCHRONOUS SELF-SHIFTING CLUTCH [75] Inventors: Herbert Arthur Clements,

Weybridge; Robert Howard Heybourne, Molesey, both of England [73] Assignee: S.S.S. Patents Limited, London,

England [22] Filed: Oct. 29, 1973 [2]] Appl. No.: 410,453

[30] Foreign Application Priority Data Oct. 3l, I972 Great Britain 50203/72 [52] US. Cl 192/67 A, 192/104 F, 192/114 R [51] Int. Cl. F16d 23/02 [58] Field of Search 192/67 A, 103 F, 104 F, 192/114 R [56] References Cited UNITED STATES PATENTS 2,556,678 6/1951 Crafts l92/ll4 2,733,79l 2/1956 Short 192/114 X 3,272,295 9/1966 Clements 192/114 X 3,715,019 2/1973 Heybourne et al. 192/114 R X Primary Examiner-Allan D. Herrmann Attorney, Agent, or FirmWoodoock, Washburn, Kurtz & Mackiewicz [57] ABSTRACT In a synchronous self-shifting toothed clutchhaving an intermediate member movable relative to one of the clutch parts to effect at least partial interengagement of the clutch teeth, the said clutch part carries a ring of baulking teeth and the intermediate member carries a toothed locking ring which is rotatable about the clutch axis. In the disengaged condition of the clutch the locking teeth and the baulking teeth are interengaged when the clutch teeth attain at least partial in terengagement the locking teeth move axially out of engagement with the baulking teeth and the locking ring is rotated by springs to a position in which disen gagement of the clutch teeth is prevented due to the baulking teeth being in baulking relationship with'the locking teeth.

Fluid pressure acts automatically, when the clutch attains a predetermined rotational speed, to return the locking ring to a position in which the locking teeth can interengage with the baulking teeth to permit the clutch to disengage.

5 Claims, 5 Drawing Figures This invention relates to synchronous self-shifting toothed clutches of the type comprising first and second rotary clutch parts, with clutch actuating mechanism operative upon passage of the first and second rotary clutch parts through synchronism in one direction of relative rotation, the said mechanism including an intermediate member constrained for movement relative to one of said first and second rotary clutch parts to effect at least initial interengagement of the coacting clutch teeth.

Clutches of the type referred to above are normally provided with pawl and ratchet mechanism or equivalent means such that upon relative rotation of the first and second rotary clutch parts in one direction the clutch overruns, whereas upon passage of the first and second rotary clutch parts through synchronism in the other direction of relative rotation the pawl and ratchet mechanism or equivalent means operates to effect movement of the intermediate member to bring the coacting clutch teeth into precise initial interengagement.

It is frequently a requirement that the clutch should includemeans operable to prevent disengagement of the interengaged clutch teeth, such that the clutch is then capable of transmitting torque in both directions of rotation. However, such means as have previously been provided for this purpose have certain disadvantages. For example, the said previously provided means have added to the overall length of the clutch, and moreover have generally required to be actuated by means of a servo mechanism through the intermediary of a control fork. thus adding to the complexity of the construction.

The object of the invention is to provide, in a clutch of the type referred to above, improved means for preventing disengagement of the interengaged clutch teeth, which means do not have the disadvantages of prior arrangements for this purpose.

In accordance with the invention, a clutch of the type referred to above includes means operable to prevent disengagement of the interengaged clutch teeth, the said means comprising locking means carried by the intermediate member or by the said one rotary clutch part, and baulking means carried by the said one rotary clutch part or by the intermediate member, said locking means and said baulking means being capable, when the clutch teeth are at least partially interengaged, of relative rotational movement about the clutch axis between a baulking condition in which disengagement of the clutch teeth is prevented owing to the said baulking means being in axial baulking relationship with said locking means, and a non-baulking condition in which disengagement of the clutch teeth is permitted owing to the said baulking means being out of axial baulking relationship with said locking means.

The relative rotational movement of the baulking means and the locking means to provide a baulked condition may be arranged to take place under the action of one or more springs which take effect automatically when the clutch teeth are at least partially interengaged. The relative rotational movement of the baulking means and the locking means to provide an unbaulked condition may be effected by the action of fluid pressure acting in opposition to the force of the spring or springs. In the embodiment of the invention now to be described the force of the spring or springs 2 is arranged to be overcomeautomatically by fluid pressure when the clutch attains a predetermined rotational speed.

In the accompanying drawings:

FIG. 1 is a view in side sectional elevation of a synchronous self-shifting toothed clutch embodying the invention, the upper half of FIG. ll showing the clutch in a disengaged condition and the lower half of the figure showing the clutch in an engaged condition,

FIG. 2 is a view in side sectional elevation of the lower part of the clutch shown in FIG. I, with the clutch teeth partially disengaged,

FIG. 3 is a section on the line III-Ill of FIG. 1,

FIG. 4 is a section on the line IV-IV of FIG. 1, and

FIG. 5 is a section on the line V-V of FIG. 2.

Referring to the drawings, a first rotary clutch part includes a sleeve 1 formed with a flange l which is drivably connected to a flange 2 on a shaft 3. The sleeve 1 is formed with a ring of internal clutch teeth 4 and with a ring of internal ratchet teeth 5. A second rotary clutch part includes a sleeve 6, formed with a flange 6' which at its outer periphery is formed with a sleeve 7. The sleeve 6 is formed with external righthand helical splines 8; The flange 6 is drivably con nected to a flange 10 which is provided on a shaft 11 and which is formed to provide an oil catcher ring 12, to which oil can be fed from an external source through a jet 13. The intermediate member of the clutch includes a sleeve 14 formed with internal helical splines 15 which are engaged with the external helical splines 8 on the sleeve 6. The sleeve 14 is formed with a ring of external clutch teeth 16, and carries pawl pins 17 on which are mounted pawls 18, which are provided with control springs (not shown). The noses of the pawls 18 point in anti-clockwise direction when viewed from the left-hand end of FIG. 1. The sleeve 14 is also formed with a radially outwardly projecting annular flange 19, which at its outer periphery carries a locking ring carrier 20 to which is fixed a control ring 21 a surface 21' of which is in sliding contact with the outer surface of the sleeve 7. The locking ring carrier 20 is formed with radially inward projections 22 which project intoarcuate recesses 23 in the outer surface of a locking ring 26. The locking ring 26 is capable of angular sliding movement relative to the locking ring carrier 20, the said movement being limited by rotational stops 27 carried by the locking ring carrier, the stops 27 projecting radially inwardly into arcuate recesses 28 in the locking ring 26 and being in sliding contact with the locking ring. The locking ring 26 is formed] with a ring of internal locking teeth 29.

The sleeve 7 carried by the second rotary clutch part 6 is formed with a ring of external baulking teeth 30. It is also formed with radial oil feed ducts 31 which communicate via ducts 32, 33 and 34 in the secondary rotary clutch part with ducts 36 in the flange 10, the ducts 36 opening into the annular oil chamber ofthe oil catcher ring 12. The control ring 21 is formed with ducts 37 each of which communicates at its radially outer end with one of the recesses 28 in the locking ring 26, and at its radially inner end with an annular chamber 38 formed in the control ring .21.

Each of the arcuate recesses 23 in the locking ring 26 accommodates in compression spring 39, one end of which bears against the associated projection 22 and the other end of which bears against an end wall of the recess 23. The projections 27 are adapted to serve as pistons, and the recesses 28 are adapted to serve as piston chambers.

With the clutch disengaged, as shown in the upper half of FIG. 1, the pawls 18 are axially positioned for ratcheting relative to the ratchet teeth 5. The locking teeth 29 are interengaged with the baulking teeth 30 (see FIG. 3). The ducts 31 are blanked by the surface 21' of the control ring 20.

For the purpose of description it will be assumed that the shaft 3 is the shaft of a generator, that the shaft 11 is the shaft of a gas turbine, and that a starting motor connected to shaft 3 is to be used for starting the gas turbine from rest.

Initally, the shaft 3 of the generator is rotated in the direction shown by the arrow in FIG. 1, thereby causing pawls 18 to engage ratchet teeth 5, whereby under the action of the interengaged helical splines 8 and the intermediate member 14 is shifted helically relative to the second rotary clutch part 6 (to the right in the upper half of FIG. 1) so as to bring the external clutch teeth 16 carried by the intermediate member into precise initial interengagement with the internal clutch teeth 4 carried by the first rotary clutch part 1. During this movement of the intermediate member the locking ring carrier moves helically relative to the sleeve 7 (in clockwise direction in FIG. 3) and since the locking teeth 29 and the baulking teeth are interengaged the locking ring. carrier 20 is rotated relative to the locking ring 26 (in clockwise direction in FIG. 3), the effect of which is to increase the compression of the springs 39. The locking teeth 29 then slide axially out of engagement with the baulking teeth 30, whereupon the springs 39 cause the locking ring 26 to rotate relative to the baulking teeth (in the clockwise direction in FIG. 3) so that the locking teeth 29 become axially aligned with the baulking teeth 30 (see FIG. 4).

It is now possible to start the gas turbine by means of the starting motor, which is used to rotate the shaft 3 in the direction (opposite to the arrow in FIG. 1) such that in the absence of the baulking condition due to the axial alignment of the locking teeth and the baulking teeth the partially interengaged clutch teeth 4 and 16 would disengage. However, such disengagement is prevented owing to the locking teeth 29 being baulked by the baulking teeth 30, and the clutch is capable of transmitting torque in what would otherwise be the overrunning condition.

When the gas turbine starts to produce output power, the consequent rotation of the shaft 11 relative to the shaft 3 and the interaction of the partially interengaged clutch teeth 4 and 16 causes the intermediate member 14 to be shifted to the right relative to the second r0- tary clutch part 6 under the action of the helical splines 8 and 15, causing the clutch teeth 16 to engage fully with the clutch teeth 4. This movement of the interme diate member 14 causes the baulking teeth 30 to be re lieved of the end load of the locking teeth 29 (see the lower half of FIG. 1). During this movement of the intermediate member 14 the annular chamber 38 in the control ring 21 comes into communication with the radial ducts 31, and as the rotational speed of the system increases oil from the catcher ring 12 is urged by centrifugal force towards the ducts 31 and thence via the annular chamber 38 and the ducts 37 into the piston chambers 28. As the rotational speed of the system increases further the oil pressure in the piston chambers 28 rises under the action of centrifugal force until,

when the system attains a predetermined rotational speed, the oil pressure in the piston chambers 28 is sufficient to overcome the force of the springs 39 and to rotate the locking ring 26 (anti-clockwise in FIG. 4) to the position in which projections 27 abut the end walls of the recesses 28. Hence when the rotational speed of the gas turbine is reduced below the rotational speed of the generator, the clutch is able to disengage since the locking teeth 29 can interengage with the baulking teeth 30 (see FIG. 5). During disengagement of the clutch the ducts 31 become blanked by the surface 21' of the control ring 21 so that the supply ofoil to the piston chambers 28 is shut off. The oil in the piston chambers drains away through restricted orifices 38, this draining action being assisted by the action of the springs 39, by the disengaging motion of the intermediate member 14 and by centrifugal force acting on the oil in the piston chambers 28.

What is claimed is:

1. A synchronous self-shifting toothed clutch comprising first and second rotary clutch parts, coacting clutch teeth with clutch actuating mechanism operative upon passage of said first and second rotary clutch parts through synchronism in one direction of relative rotation, the said mechanism including an intermediate member constrained for movement relative to one of said first and second rotary clutch parts to effect at least partial interengagement of the coacting clutch teeth, the clutch including means operable to prevent disengagement of the clutch teeth when interengaged, characterised in that the said means comprise locking means carried by the intermediate member or by the said one rotary clutch part and baulking means carried by the said one rotary clutch part or by the intermediate member, with means mounting said locking means and said baulking means whereby said locking means and said baulking means are capable, when the coacting clutch teeth are at least partially interengaged, of relative rotational movement about the clutch axis between a baulking condition in which disengagement of the clutch teeth is prevented owing to the said baulking means being in axial baulking relationship with said locking means and a non-baulking condition in which disengagement of the clutch teeth is permitted owing to the said baulking means being out of axial baulking relationship with said locking means.

2. A synchronous self-shifting toothed clutch according to claim 1, wherein said locking means include a ring of locking teeth and said baulking means include a ring of baulking teeth, and wherein in the said baulking condition said locking teeth and said baulking teeth are positioned in at least partial axial alignment and in the said non-baulking condition said locking teeth and said baulking teeth are positioned for interengagement.

3. A synchronous self-shifting toothed clutch according to claim 1, including spring means operative automatically, when the coacting clutch teeth are at least partially interengaged, to produce relative rotational movement of said locking means and said baulking means to provide said baulking condition.

4. A synchronous self-shifting toothed clutch according to claim 1, including fluid pressure means for producing relative rotational movement of said baulking means and said locking means to the non-baulking condition.

5. A synchronous self-shifting toothed clutch according to claim 1, including fluid pressure means that operate automatically to produce relative rotational movement of said locking means and said baulking means to a non-baulking condition when, with the coacting clutch teeth at least partially interengaged, the clutch attains a predetermined rotational speed. 

1. A synchronous self-shifting toothed clutch comprising first and second rotary clutch parts, coacting clutch teeth with clutch actuating mechanism operative upon passage of said first and second rotary clutch parts through synchronism in one direction of relative rotation, the said mechanism including an intermediate member constrained for movement relative to one of said first and second rotary clutch parts to effect at least partial interengagement of the coacting clutch teeth, the clutch including means operable to prevent disengagement of the clutch teeth when interengaged, characterised in that the said means comprise locking means carried by the intermediate member or by the said one rotary clutch part and baulking means carried by the said one rotary clutch part or by the intermediate member, with means mounting said locking means and said baulking means whereby said locking means and said baulking means are capable, when the coacting clutch teeth are at least partially interengaged, of relative rotational movement about the clutch axis between a baulking condition in which disengagement of the clutch teeth is prevented owing to the said baulking means being in axial baulking relationship with said locking means and a non-baulking condition in which disengagement of the clutch teeth is permitted owing to the said baulking means being out of axial baulking relationship with said locking means.
 2. A synchronous self-shifting toothed clutch according to claim 1, wherein said locking means include a ring of locking teeth and said baulking means include a ring of baulking teeth, and wherein in the said baulking condition said locking teeth and said baulking teeth are positioned in at least partial axial alignment and in the said non-baulking condition said locking teeth and said baulking teeth are positioned for interengagement.
 3. A synchronous self-shifting toothed clutch according to claim 1, including spring means operative automatically, when the coacting clutch teeth are at least partially interengaged, to produce relative rotational movement of said locking means and said baulking means to provide said baulking condition.
 4. A synchronous self-shifting toothed clutch according to claim 1, including fluid pressure means for producing relative rotational movement of said baulking means and said locking means to the non-baulking condition.
 5. A synchronous self-shifting toothed clutch according to claim 1, including fluid pressure means that operate automatically to produce relative rotational movement of said locking means and said baulking means to a non-baulking condition when, with the coacting clutch teeth at least partially interengaged, the clutch attains a predetermined rotational speed. 